Presently, thermally compensated thermostat metal actuated electrical devices use a thermostat metal, such as bimetal, compensator to provide relatively constant levels of hold and trip currents as a function of ambient temperature. However, in providing suitable thermostat metal compensation for a series of devices having different current ratings the level of compensation must be changed appropriately. To provide for a range of compensation that may be needed as one goes from one ampere rating to the next, different thickness thermostat metals and different types metals for the thermostat metals are used to obtain varying levels of bimetal activity (movement per degree Fahrenheit). The formula for thermostat metal movement is shown below:B(thermostat metal movement)=0.53F(ΔT)L2/t                Where F is flexivity (10−7/degree Fahrenheit), T is degrees Fahrenheit, thermostat metal movement B, length L and thickness t are in inches.        
As noted above, it is known to use different thickness thermostat metals to obtain different levels of compensation, i.e., different amounts of movement per degree of temperature, for example 0.023, 0.026, 0.028, 0.030 inch thickness. However, this approach for changing compensation levels has several disadvantages. The first disadvantage is that this approach is relatively expensive to provide because manufacturing different thicknesses requires the use of heavy rolling mills and the like that produce large quantities of material while only small quantities are needed for each rating of compensation members thereby resulting in excessively large amounts of inventory. Further, the mass of the compensators and associated latches for higher ratings increase along with thickness making the circuit breakers more sensitive to shock and vibration.
Changing the length of the thermostat metal compensator is impractical because of packaging constrains. That is, designers of equipment with which the devices are to be used, such as aircraft, typically are not able to accommodate device packages of different sizes.